Consumers and manufacturers are increasingly concerned with the environmental impact of all products and product packaging. Perhaps the single greatest environmental concern for consumers, and consequently for manufacturers, is global warming and the greenhouse gases that contribute to global warming. Greenhouse gases are gases that allow sunlight to freely enter the Earth's atmosphere. When sunlight strikes the Earth's surface, some of the sunlight is reflected back towards space as infrared radiation. Greenhouse gases absorb the infrared radiation thereby trapping heat in the Earth's atmosphere. Over a period of time, the amount of energy sent from the sun to the Earth's surface should be about the same as the amount of energy radiated back into space resulting in the temperature of the Earth's surface being approximately constant. However, the increase in the quantity of greenhouse gases above the quantity that existed before the rise of human industrialization is thought to have increased the retained heat on the Earth's surface and leads to global warming.
Carbon dioxide (CO2) has been singled out as the largest component of the collection of greenhouse gases in the atmosphere. For example, the level of atmospheric CO2 has increased by approximately 50 percent in the last two hundred years. The increasing amount of CO2 introduced into the atmosphere by fossil fuel-based materials is believed to be a large contributor to the greenhouse gas effect and the increase in global temperatures. Consumers and environmental protection groups alike have identified industrial release of carbon into the atmosphere as the source of carbon causing the greenhouse effect. However, organic products composed of carbon molecules from renewably based sources, such as plant sugars and starches, are considered to not further contribute to the greenhouse effect compared to the same organic molecules that are petroleum or fossil fuel based.